Scanning T.V. cameras are intended for use in inspection, particularly in the inspection of relatively inaccessible areas such as the interiors of sewers and other pipe-lines, and also in other applications such as surveillance; one example of a scanning T.V. camera is the subject of our published British Patent Application, No. 2210530 A, the contents of which are incorporated herein by reference.
Cameras for these purposes should have a wide field of view, usually incorporate a wide-angle lens, and are provided with operating mechanisms to effect scanning of the area to be inspected; surveillance cameras often incorporate a telescopic lens. T.V. cameras usually now incorporate a CCD (charged coupled device) image sensor in the focal plane of the lens, and the sensor can be shifted on the X and Y axes to produce the tilt/pan effects for scanning. Alternatively, the camera may comprise a Vidicon tube which carries an end target sensor and which can be pivoted or otherwise moved to swing the target across the focal plane area of the lens. Suitably, the CCD sensor or Vidicon tube is driven by first and second electric motors that drive to X-Y positions which are detected by relative and absolute feed-back sensors.
It is an object of the present invention to provide a scanning T.V. camera having provision for indicating the section of the field of view which is being inspected.